Mexico City, Jan 19 (efe-epa).- The death toll from a huge explosion caused by an illegal pipeline tap in the central Mexican state of Hidalgo has climbed to 66 - up from an earlier figure of 21, officials said Saturday morning.

"The toll we have at the moment from what occurred in (the small town of) Tlahuelilpan is 66 people dead and 76 people injured, who are being treated at different hospitals," the state's governor, Omar Fayad, said on Twitter.

Many of the injured suffered severe burns, and authorities fear that more charred bodies will be found near the pipeline. Hundreds of people had gathered to collect fuel after thieves had drilled a hole in the duct on Friday afternoon.

Mexican President Andres Manuel Lopez Obrador, who has been waging a battle against the illegal trade in stolen fuel (known in Mexico as "huachicoleo") since taking office late last year, a crackdown that has caused widespread shortages at service stations, urged people in a press conference Saturday morning to stop committing this crime.

"We are sincerely saddened by what happened and also ... want to tell the families of the injured that we're providing special attention at hospitals and are trying to save lives," the leftist head of state, known as AMLO, said.

Fayad said at the press conference that when the leak was discovered an attempt was made to cordon off the area but that the task was impossible because hundreds of people had gathered at the site.

Of those injured in the explosion, which occurred at 6.50 pm Friday, 73 are men and three are women.

Stealing fuel from pipelines owned by state oil company Petroleos Mexicanos (Pemex) and re-selling it on the black market has become a major criminal enterprise in Mexico.

Theft of fuel from pipelines cost Mexico some $3.4 billion last year, the government says.

Since his Dec. 1, 2018, inauguration, Lopez Obrador has launched an all-out fight against this scourge.

The president has deployed thousands of security forces to bolster security at pipelines (a frequent target of fuel thieves).

His administration also adopted a change in Pemex's method for shipping gasoline and diesel from refineries to urban distribution centers, opting to transport more fuel via tanker trucks instead of pipelines.

That modification has caused severe supply problems in at least 10 states and in Mexico City and led to the closure of service stations, panic purchases and attempts to sabotage pipelines.